When the show starts, not a thing goes wrong. First there are demonstrations of what this new generation of wrenches has learned. Deirdre and her twin sister from Mattapan command crowds two and three deep as they repack a hub. At another station, Lucie and Pretzel pass out the class-made cookbook focusing on unadorned, nutritionally power-packed items. Even Allen Lim would be ­hard-pressed to argue with the simple brilliance of page one’s “boiled eggs.”

As well as all this goes, it’s mere prelude to the show-stopping part of the evening when the students are individually introduced, awarded graduation ribbons (with chainring medals), and allowed to roll out their bikes in public for the first time. Chairs are rearranged to create a runway; music is cued, and to mad ­applause the parade begins. There are BMX bikes, cruisers, and vintage three-speeds. At first there is a little self-consciousness with all eyes on each graduate and their works. But by the time Lucie rolls out her bike—flat bar and all—she is full of unabashed enthusiasm, pounding high fives with everyone along her route. The final punctuation is a “whoop-whoop” that might’ve been heard at the Stony Brook Orange Line stop. For the next 10 minutes, there is bedlam. A dark, cold Tuesday in November might be the best day of the whole year of cycling in this city.

Both my children and two of their friends—who in my enthusiasm I entreatied into accompanying me—will tell me afterward that they can’t believe how cool it was. My son and daughter will later ­enroll in their school’s bike advocacy elective, and one their friends, Amadu, will raise $1,400 for charity at his private school with—what else?—a tweed ride. I’m not unaffected, either. I will begin by picking up the garage from last summer, then figuring out how to overhaul the brakes on my town bike and getting my brother to join me in a membership at the local wrench collective. In the months to come, I will end up going deeper still. I’ll help start up a local bike committee. I’ll volunteer to teach a three-week course at the local private school and, at the close of school, the students will hold a bike drive, collecting 120 bikes to donate to BNB. A few family members will ask if I might have stumbled into a new career, since, they say, I seem to have such a enthusiasm for spreading the gospel of bikes.

But for right now, amid riotous family, Fatima is giving out and receiving hugs. It is her first graduation. We all want to earn a bike.